1. Field of the Invention
The present invention relates to a color solid-state imager and to a method of making the same.
2. Description of the Prior Art
The following method has heretofore been employed to make filters for decomposing the colors. Namely, a glass substrate is coated with a photosensitive liquid composed of a polyvinyl alcohol having photosensitive properties to form a photosensitive film. The photosensitive film is irradiated with light through a mask so that portions corresponding to a first color are optically hardened. The portions are then developed and are allowed to be left. A filter member composed of the photosensitive film is dyed with a dye having predetermined spectral characteristics. Then, a transparent intermediate layer is formed on the whole surfaces. The same procedure holds true for a filter member of a second color. Namely, the glass substrate is coated with the above-mentioned photosensitive liquid to form a photosensitive film, irradiated with light through a mask, and is developed to form a filter member of the second color. The filter member is dyed with a dye having predetermined spectral characteristics. Then, a transparent intermediate layer is formed on the whole surfaces. A filter member of a third color is then formed in the same manner, dyed with a dye, and is coated with a top film which serves as a protection film, thereby to obtain a complete color filter.
There has been proposed a color solid-stage imager constructed by placing a filter for decomposing color on a solid-state imager.
Such a color solid-state imager has generally been produced by separately making solid-state imagers and color-decomposing filters, and bringing the two elements into alignment to stick them together using an optical adhesive agent or the like. There has also been reported to use an optical matching oil in place of the optical adhesive agent.
It is not allowed to directly apply the above-mentioned method of making filters to a semiconductor substrate for solid-state imagers. It is because, the solid-state imagers have bonding pad portions which are not possessed by generally employed filters.
The following reference is cited to show the state of the Prior Art.
P. L. P. Dillon et al. International Electron Device Meeting 1976, Dec pp. 400-403.